bug#43668: Daemon tries to build GNU/Hurd derivations on GNU/Linux

[Ludovic Courtès]

Here’s the problem:

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$ guix build guile-bootstrap -s i586-gnu
La jena derivo estos konstruata:
   /gnu/store/xi7r3bryibnyvjrs6avv8qp676mja4w2-guile-bootstrap-2.0.drv
building /gnu/store/xi7r3bryibnyvjrs6avv8qp676mja4w2-guile-bootstrap-2.0.drv...
builder for 
`/gnu/store/xi7r3bryibnyvjrs6avv8qp676mja4w2-guile-bootstrap-2.0.drv' failed 
due to signal 11 (Segmentation fault)
build of /gnu/store/xi7r3bryibnyvjrs6avv8qp676mja4w2-guile-bootstrap-2.0.drv 
failed
View build log at 
'/var/log/guix/drvs/xi/7r3bryibnyvjrs6avv8qp676mja4w2-guile-bootstrap-2.0.drv.bz2'.
guix build: error: build of 
`/gnu/store/xi7r3bryibnyvjrs6avv8qp676mja4w2-guile-bootstrap-2.0.drv' failed
$ uname -o
GNU/Linux
$ guix describe 
Generacio 160   Sep 25 2020 23:40:20    (nuna)
  guix a0d4aa2
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: a0d4aa2457d7e36012143ffe3fbc9dd4bc20ca4f
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It’s no wonder that the GNU/Hurd executable fails to run on GNU/Linux.
The reason the daemon tries to run it anyway is because of the hack
introduced in 7bf2a70a4ffd976d50638d3b9f2ec409763157df, in support of
transparent emulation via binfmt_misc.

Ludo’.